In this post we’ll go through a few basic concepts that we need to know before starting to write code. After clearing this out, you’ll write your first Go lang program, the classic hello world.
Basic Concepts
Code
As programmers we write software but we don’t spend the time sending a huge stream of 0s and 1s to tell the computer
what we want it to do. That process would be very prone to errors and it would make the instructions completely
unreadable to other humans, not to mention the time it would take to write such code.
For those reasons, among others, we rely on higher level1 languages to produce human readable instructions that can be easily transformed to some other language that the computer can understand. That original version of the software written in a human readable language, using one or more programming languages, is what we call source code2 or for short just code.
This code will go into a compiler or interpreter to be processed and converted to a lower level code, also named machine code, which can be understood by the computer. Once the code passes through the compiler or interpreter, the result is no longer human readable, but can be executed directly in the computer’s CPU3.
The machine code is assembled in a specific instruction set that comprises arithmetic, logic, memory and other operations that tell the computer what to do exactly4.
Compilers and Interpreters
To put it in simple words a compiler is a translator, that reads source code in a programming language and outputs an equivalent code in another. Generally speaking the target is a lower level language that can be understood by the computer5.
Interpreters are also a type of translator, but they work in a different way. While compilers go through all the source code scanning, processing and translating it in its entirety, an interpreter will do the process statement by statement6. That is, it will process the single instruction, check its validity and run it before going to the next line. The process is explained, in a very simplified fashion, in in the following graphics5:
Compiled vs. Interpreted
These translators have several responsibilities, one of the more important ones is to check and announce if the source code has any errors, they do this while translating the source5. Both compilers and interpreters do this and. in general terms. they both accomplish the same grand task: translating and executing a program. However, their inner workings are very distant.
When first checking out this topic a question comes to mind: which one is better? And the answer is simply, each one is better at different chores. For example, the machine code produced by a compiler appears to be much faster than the interpreted counterpart, but the latter will usually be capable of giving more precise error information if something goes wrong5.
| Compiler | Interpreter |
|---|---|
| Better performance of executable | Code executes directly |
| Higher degree of optimization | Better error reporting |
The important aspect is that you can communicate with the computer with both techniques, you can do the same operations with both and you will end up with a piece of software that can be run by the computer.
Your First Programming Language
To start writing code, we must first choose one of the multitude of languages that exist and learn the correct syntax. For our purposes we are going to start with Go lang.
A (very) Brief History of Go
Go is a programming language designed by a team of Googlers7, its syntax is similar to C, but improving greatly on lots of places where C lacks, e.g.: memory safety, garbage collection and concurrency8.
Although this language is compiled and uses static types9, it has certain features that can be confused with dynamic typing (e.g.: type inference on variable declaration), but this is only due to Go’s focus on simplicity. Some of the characteristics that describe Go are10:
- Static typing
- Efficiency
- Readability and usability
- High-performance networking
- Native concurrency
- Fast compilation
- Package/dependency management
With all these properties in mind, the creators decided to leave out some features that other languages have.
Hello World
As it is tradition around here, your first program will be a simple hello world. For now accept the words that are shown here, you can go play with this extract of code in the Go Playground.
The source code:
package main
import (
"fmt"
)
func main() {
fmt.Println("Hello world, I'm learning programming fundamentals!")
}
And the result will be:
Hello world, I'm learning programming fundamentals!
Program exited.
Now go play with this code, make it say hi, bye, a number or your favourite poetry extract.
Further Reading
Compilers and Interpreters. Compiler definition, internal structure and how they work. Get this book: Compilers: Principles, Techniques, and Tools by Alfred Aho, Monica Lam, Ravi Sethi, Jeffrey Ullman.
Compilers and Interpreters. A non academic and simple explanation of what interpreters are. Wikipedia: Interpreter (computing).
Go Lang. A brief history of the language. Wikipedia: Go (programming language).
Go Lang. Very good tutorial of the syntax and all the main features of the language. A Tour of Go. Do this tutorial if you want to rush through all features the language has to offer, but I will detail the basics in future posts.
Footnotes and References
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The higher the level of the language, the closer it is to natural language. Likewise, the lower the level, the closer to machine language. ↩
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The Linux Information Project. Source Code Definition. URL. Accessed: 2019-06-01. ↩
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Wikipedia. Instruction set architecture. URL. Accessed: 2019-06-01. ↩
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Alfred Aho, Monica Lam, Ravi Sethi, Jeffrey Ullman. Compilers: Principles, Techniques, and Tools. Pearson Education, Inc. Second Edition. 2006. ↩ ↩2 ↩3 ↩4
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StackOverflow. Compiled vs. Interpreted Languages. URL. Accessed: 2019-06-03 ↩
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A googler is a person who works at Google 🤷. ↩
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Wikipedia. Go (programming language). URL. Accessed: 2019-06-03 ↩
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We’ll see what static and dynamic types mean in the next post. ↩
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Pike, Rob (April 28, 2010). “Another Go at Language Design”. Stanford EE Computer Systems Colloquium. Stanford University. Video available. ↩
